#include <bits/stdc++.h>
#define ll long long
#define debug(...) fprintf(stderr,__VA_ARGS__)
using namespace std;

inline static int read(){
    int sum=0,neg=0,ch=getchar();
    while(!isdigit(ch)) neg|=(ch=='-'),ch=getchar();
    while(isdigit(ch)) sum=sum*10+(ch^48),ch=getchar();
    return neg?-sum:sum;
}
int N=100;
int C[2000][2000];

signed main(){
    // freopen("oi.in","r",stdin);
    // freopen("oi.out","w",stdout);
    for(int i=0;i<=N;C[i][0]=1,i++) for(int j=1;j<=i;j++) C[i][j]=C[i-1][j]+C[i-1][j-1];
    int x=read();
    cerr<<C[x*3][x]/(2*x+1);
    return 0;
}
